1. Field
Example embodiments relate to cholesteric liquid crystal display devices having a single-layered structure and methods of manufacturing the same.
2. Description of the Related Art
As flexible displays such as electronic paper (e-paper) are actively developed, use of a display device using a cholesteric liquid crystal is receiving more attention.
A cholesteric liquid crystal is a liquid crystal composition formed by twisting a nematic liquid crystal into a helix structure. A cholesteric liquid crystal has a light reflection property, which varies according to a helix pitch. More specifically, light having a given, desired or predetermined wavelength range is selectively reflected according to a helix pitch of a liquid crystal molecule. Thus, a full-color image is produced by controlling a reflection wavelength range by using pixels having different helix pitches. A cholesteric liquid crystal having these display characteristics has relatively clear color display characteristics, relatively high contrast characteristics, and relatively high resolution characteristics. A display device using cholesteric liquid crystals shows relatively high performance.
A method of producing a full-color image using cholesteric liquid crystals is performed in a multilayer manner or a single layer manner. According to the multilayer manner, for example, a red (R) pixel, a green (G) pixel, and a blue (B) pixel are stacked on each other. The red (R) pixel has a helix pitch that is controlled such that light having a red wavelength range is selectively reflected. The green (G) pixel has a helix pitch that is controlled such that light having a green wavelength range is selectively reflected. The blue (B) pixel has a helix pitch that is controlled such that light having a blue wavelength range is selectively reflected. The respective pixels are controlled to be in a wavelength selection reflection mode or transmission mode, according to the application of a voltage, and a color corresponding to a pixel being in the wavelength selection reflection mode is displayed. However, the multilayer manner is relatively complicated and expensive at least because a multi-layer substrate is used. In addition, the multilayer manner also provides relatively low color purity due to a scattering phenomenon that may occur in a pixel that is in the transmission mode.